Use thinly sliced pancetta or you could use streaky bacon I suppose - I'm sure it would be just as nice.,Slice the cheese into thinnish slices.,Grate the cold potatoes using the coarse side of the grater.,Using a large non stick frying pan (Large - so you can use it to fry the potato cakes afterwards).,Fry the slices of pancetta until the fat turns golden. Then remove and set to one side.,Season the potatoes with salt and pepper.,Shape with your hands into flat patties - you should have enough to make about six.,Melt the butter with the olive oil in the pan. When the butter starts to fizz, using a slotted metal slice, slide three of the potato cakes inches Be careful as you do that they don't spit.,Cook over a moderate heat until they are golden underneath.,Now carefully, so they don't break, turn them over. If they do break don't fuss just shape them best you can and carry on - they'll taste just as good.,Cook until both sides are golden.,Take them out and keep warm while you repeat with the remaining cakes.,Return the cooked cakes to the pan.,Divide the cooked pancetta between the cakes and lay the cheese on top.,______,Serve immediately.